class Solution {
public:
    int evalRPN(vector<string>& tokens) {
        stack<int> st;
        for(auto e:tokens)
        {
            if(e=="+"||e=="-"||e=="*"||e=="/")
            {
                int right=st.top();
                st.pop();
                int left=st.top();
                st.pop();
                switch(e[0])
                {
                   case '+':
                   st.push(left+right);
                   break;
                   case '-':
                   st.push(left-right);
                   break;
                    case '*':
                    st.push(left*right);
                    break;
                    case '/':
                    st.push(left/right);
                    break;
                }
            }
            else
                st.push(stoi(e));
        }
        return st.top();
    }
};
